JP4574178B2 - Manufacturing method of anti-fogging articles - Google Patents

Description

  The present invention relates to a method for producing an antifogging article in which an antifogging film made of a urethane resin is formed on a base material.

  In order to achieve both anti-fogging properties and wear resistance, anti-fogging coatings utilizing the hydrophilic properties of surfactants and the wear resistance due to the elasticity of urethane resins have been studied. For example, Patent Document 1 discloses an antifogging film made of a urethane resin obtained by reacting a chemical species having an NCO group with a surfactant having a functional group that reacts with a hydrophilic polyol and an NCO group. .

  An antifogging article is obtained by applying a coating solution to a substrate and then forming a cured film on the substrate by heating. In making the anti-fogging article into an industrial production, it is necessary to reduce the number of coatings which are not sufficiently cured as much as possible. A film that is not sufficiently cured tends to have insufficient hardness, abrasion resistance, anti-fogging properties, etc., and easily leads to deterioration of quality. It is also expected that the surfactant will flow out of the cured coating.

  Therefore, in order to control the curing of the coating, it is important to adjust the number of NCO groups and the number of active hydrogen groups such as hydroxyl groups when preparing the coating solution in order to improve the productivity of the antifogging article. is there. Patent Document 2 discloses that the equivalent ratio of NCO group / hydroxyl group is 0.2 to 5.0 in the polyurethane coating composition. Patent Document 3 discloses 0.9 to 1.3 as a particularly preferable range.

However, these have not been studied for an appropriate ratio for improving the productivity of the antifogging article, and there is no suggestion about an appropriate heating temperature, heating time and the like after application to the substrate. Depending on the substrate, there is a limit to the temperature at which heating is possible, and it is necessary to set an appropriate ratio in order to improve productivity. In order to prevent the surfactant from flowing out of the coating, there are measures such as making the coating solution homogeneous and ensuring sufficient curing time. However, these measures are the cause of high costs. It becomes.
JP 2000-515572 A JP-A-10-306256 JP-A-11-279484

  A method for reducing the curing failure of an antifogging article formed by curing an antifogging film of a urethane resin containing a surfactant on a base material and facilitating management of a coating liquid for forming the film. It is another object of the present invention to provide an antifogging article that does not deteriorate the antifogging performance even after the protective film is adhered and peeled even if it is cured at a low temperature for a short time.

The method for producing an antifogging article according to the present invention includes a chemical species having an NCO group, a surfactant having an active hydrogen group, and a polyol (these three chemical species are collectively referred to as “antifogging urethane component” hereinafter). Is a method of obtaining an anti-fogging article by applying a coating solution obtained by mixing the above to a substrate, wherein the NCO group number / active hydrogen group number is 0.8 or more and 1.2 or less, preferably 0.9 or more. 1.15 or less, forming a cured film after applying the coating liquid to the substrate, and removing the surfactant having unreacted active hydrogen groups from the film by bringing water into contact with the cured film It shall be the feature. Here, the active hydrogen group is a group that reacts with an NCO group such as a hydroxyl group, an amino group, or a mercapto group to form a bond with the group. And after apply | coating a coating liquid to a base material, it is preferable to heat at 80 to 140 degreeC.

By setting the number of NCO groups / number of active hydrogen groups to 0.8 or more and 1.2 or less , the elasticity inherent to urethane is easily generated, the wear resistance of the coating is improved, and the antifogging article is used for a long time. However, in order to obtain an antifogging article, a surfactant having an active hydrogen group is introduced into the coating solution. The surfactant becomes a side chain or a terminal when a urethane resin is formed, and therefore does not form a resin cross-link. Therefore, when the content is excessive, the strength of the coating is lowered. Anti-fogging property does not appear. Therefore, when producing anti-fogging articles, it is necessary to set an appropriate amount of surfactant, but at the time of mass production of anti-fogging articles, unreacted due to factors such as being added in an excessive amount than the appropriate amount. Often, a defect in which a surfactant having the active hydrogen group remains is generated. This defect causes the surfactant to flow out from the coating over time, causing appearance defects such as cloudiness of the coating, and a gradual decrease in antifogging properties.

In order to solve the above problems, the present invention has found that it is effective to bring water into contact with a coating formed by curing after applying a coating solution to a substrate. After curing, the surfactant having unreacted active hydrogen groups is removed from the coating by bringing water into contact with the coating. Thus, a uniform film can be obtained in a short production time, and it is effective in improving the productivity of the antifogging article.

  And it is preferable that the holding time at the time of heating at the said temperature shall be 20 minutes-60 minutes. If it is less than 20 minutes, the coating tends to be insufficiently cured, and if it exceeds 60 minutes, the production time becomes too long.

  Moreover, since the coating is cured in a short time and the anti-fogging article can be manufactured at a low temperature, it becomes possible to immediately apply the protective film on the coating side to the manufactured anti-fogging article. It is preferable because productivity is improved. As the protective film, an electrostatic patch or a film having an adhesive can be used, and a film having an adhesive is preferable. Particularly, the film having an adhesive having an adhesive strength of 1 N / 20 mm or less. Is preferred.

  According to the method for producing an antifogging article of the present invention, since unreacted surfactant is removed from the coating film, it is not necessary to strictly control the amount of surfactant in the coating solution. It becomes easy to do. Also, even if the ratio between the number of NCO groups and the number of active hydrogen groups is set close to the stoichiometric composition, it is difficult for the coating to be hardened, so that the coating tends to have elasticity inherent to urethane, and it has excellent wear resistance. Succeeded in improving the productivity of cloudy articles. Furthermore, since the heating temperature for curing can be set relatively low, a protective film can be quickly applied after the article is produced. And even if the base material is either a mirror manufactured by the silvering method and a laminated glass having an intermediate film mainly composed of polyvinyl butyral or ethylene vinyl acetate, an antifogging article is efficiently produced. To be successful.

The method for producing an antifogging article of the present invention includes a step of preparing a coating solution, a step of applying the coating solution to a substrate, and a step of heating the coated substrate to cure the coating. And it has the process of making water contact a film after hardening a film, More preferably, it has the process of sticking a protective film to an antifogging article.

  In addition to the chemical species having an NCO group, the surfactant having an active hydrogen group, and the antifogging urethane component of polyol, the coating solution can contain a filler component and a diluting solvent as necessary. Preferably, the coating liquid is prepared by mixing a chemical species having an NCO group with a mixture of a surfactant having an active hydrogen group and a polyol.

  As the chemical species having an NCO group, diisocyanate, preferably, biuret and / or trifunctional polyisocyanate having an isocyanurate structure starting from hexamethylene diisocyanate can be used. The substance has weather resistance, chemical resistance and heat resistance, and is particularly effective for weather resistance. In addition to the above substances, diisophorone diisocyanate, diphenylmethane diisocyanate, bis (methylcyclohexyl) diisocyanate, toluene diisocyanate and the like can also be used.

  As the surfactant having an active hydrogen group, anionic, cationic, zwitterionic and nonionic surfactants can be used. Anionic compounds include castor oil monosulfate, castor oil monophosphate, sorbitan fatty acid ester sulfate, sorbitan fatty acid ester phosphate, sorbitol fatty acid ester sulfate, sorbitol fatty acid ester phosphate, sucrose fatty acid ester sulfate, sucrose fatty acid ester phosphate, polyoxy Examples include alkylene castor oil ether monosulfate, polyoxyalkylene castor oil ether monophosphate, polyoxyalkylene sorbitan fatty acid ester sulfate, polyoxyalkylene sorbitan fatty acid ester phosphate, polyoxyalkylene glycerin ether monosulfate, polyoxyalkylene glycerin ether monophosphate, and the like.

  As cationic compounds, dialkanolamine salts, trialkanolamine salts, polyoxyalkylene alkylamine ether salts, fatty acid trialkanolamine ester salts, polyoxyalkylene dialkanolamine ether salts, polyoxyalkylene trialkanolamine ether salts , Di (polyoxyalkylene) alkylbenzylalkylammonium salt, alkylcarbamoylmethyldi (polyoxyalkylene) ammonium salt, polyoxyalkylenealkylammonium salt, polyoxyalkylenedialkylammonium salt, ricinoleamidopropylethyldimonium ethosulphate, etc. Is mentioned.

  Examples of zwitterionic compounds include N, N-di (β-hydroxyalkyl) N-hydroxyethyl-N-carboxyalkylammonium betaine, N-β-hydroxyalkyl-N, N-dipolyoxyalkylene-N-carboxy. Alkylammonium betaines, monoesters of N-alkyl-N, N-di (polyoxyalkylene) amines and dicarboxylic acids, N- (polyoxyethylene) -N ', N'-di (polyoxyethylene) aminoalkyl-N -Alkyl-N-sulfoalkylammonium betaines, N, N-di (polyoxyethylene) -N-alkyl-N-sulfoalkylammonium betaines, N- (β-hydroxyalkylaminoethyl) -N- (β-hydroxyalkyl) Aminoethyl carboxylic acid, N, N'-bis (2-hydroxyalkyl) -N, N'-bis (carboxyethyl) ethylenediamine salts, N-(beta-hydroxyalkyl) -N ', N'-di (polyoxyethylene) -N- carboxyethyl ethylenediamine salts.

  Nonionic types include polyoxyethylene polyoxypropylene block polymer, sorbitol fatty acid ester, sorbitan fatty acid ester, sucrose fatty acid ester, polyoxyalkylene sorbitan fatty acid ester, fatty acid monoglyceride, polyoxyalkylene fatty acid monoglyceride, polyglycerin fatty acid ester , Polyoxyalkylene castor oil ether, polyoxyalkylene alkylamine polyoxyalkylene alkylamide, and the like.

  The amount of the surfactant is preferably adjusted so that the contact angle of water droplets on the coating is 40 ° or less. By making the contact angle 40 ° or less, it becomes easy to develop antifogging properties due to hydrophilicity. In addition, when the coating has water absorption, the contact surface of the water droplet with the coating increases, so that the water absorption of the water droplet contacting the coating into the coating is promoted and the antifogging property is enhanced. Play. The smaller the contact angle is, the better the antifogging property is. However, if the contact angle is set to be small, the durability of the coating film may be deteriorated. From a practical viewpoint, the contact angle is preferably 10 ° or more. More preferably, the angle is preferably 25 ° or more and 35 ° or less. Here, the contact angle of water droplets on the coating is the contact angle when 2 μl of water is dropped on the surface of the coating that is not absorbing water.

  As the polyol, an oligomeric water-absorbing polyol can be used in order to develop anti-fogging property due to water absorption in the coating film. The water-absorbing polyol has a property of absorbing water and swells, and the hydroxyl group in the molecule reacts with the isocyanate group of the isocyanate prepolymer to form a urethane bond, thereby introducing the water-absorbing property to the urethane resin. be able to. The water-absorbing polyol may have water-soluble properties.

  In order for the film to exhibit the antifogging effect due to water absorption, the amount of water-absorbing polyol used is adjusted so that the water absorption at the time of water absorption saturation of the film is 15% by weight or more. It is preferable to use an appropriate amount of the water-absorbing component derived from polyol. The water-absorbing component may be derived from an oxyalkylene-based polyol, preferably has an oxyethylene chain, an oxypropylene chain, etc., and particularly preferably has an oxyethylene chain excellent in water absorption.

  If the water absorption rate is too high, the water resistance, hardness, wear resistance, etc. of the coating film tend to be low. Therefore, the water absorption rate of the coating film is preferably adjusted to 30% by weight or less.

  The oxyalkylene polyol preferably has a number average molecular weight of 400 to 5,000. When the number average molecular weight is less than 400, the ability to absorb water as bound water becomes low, and when the average molecular weight exceeds 5000, the strength of the coating tends to decrease. In view of water absorption and film strength, the average molecular weight is more preferably 400-4500. As the polyol, an oxyethylene / oxypropylene copolymer polyol, polyethylene glycol, or the like can be used. When polyethylene glycol is used, the number average molecular weight is 400 to 2000 in view of water absorption and the strength of the resulting film. It is preferable to do.

  As the polyol, in addition to the water-absorbing polyol, a hydrophobic polyol, a short-chain polyol having a number average molecular weight of 60 to 200, and the like can be used. The hydrophobic polyol has both flexibility and scratch resistance, and it is difficult to reduce the water absorption function and hydrophilic function of the film, and as a result, the water resistance and abrasion resistance of the film can be improved. It is preferable that it is a polyester polyol having a number average molecular weight of 500 to 2,000.

  When the number average molecular weight is less than 500, the coating film becomes too dense and wear resistance decreases. On the other hand, if it exceeds 2000, the film formability of the coating solution deteriorates and it becomes difficult to form a coating film. In consideration of the denseness of the resulting film, the polyol preferably has 2 or 3 hydroxyl groups. As the polyester polyol, any of polycarbonate polyol, polycaprolactone polyol, and a mixture thereof can be used. The hydrophobic components derived from these hydrophobic polyols are introduced so that the water absorption rate and water droplet contact angle of the coating are in the above-mentioned ranges, and the pencil hardness of the coating obtained in accordance with “JIS K 5400” is preferably When the water absorption is saturated, it is introduced so as to be HB to F.

Further, component derived from short-chain polyol increases the curing of the coating solution, the role of increasing the strength of the film, has the effect of reducing the static coefficient of friction of the film surface. The short chain polyol preferably has 2 or 3 hydroxyl groups. When the hydroxyl group is 1, the short-chain polyol does not become a skeleton component of the film, so that the film becomes fragile. When it exceeds 3, the reactivity is too active and the coating agent tends to be unstable.

Short chain polyols include ethylene glycol, propylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5 -Pentanediol, 2-butene-1,4-diol, 2-methyl-2,4-pentanediol, 2-ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, glycerin, 2- And alkyl polyols such as ethyl-2- (hydroxymethyl) -1,3-propanediol, 1,2,6-hexanetriol, and 2,2′-thiodiethanol, and alkanolamines such as diethanolamine and triethanolamine. Them alone, or a mixture, or an average of them Can be used copolymers having a molecular weight does not become more than 200, components derived from short-chain polyols can be water absorption of the film, and contact angle of water droplet is introduced so that the range described above.

  The coating liquid obtained by mixing the antifogging urethane component may contain a filler component, a diluting solvent and the like in addition to the antifogging urethane component. The filler component has the effect of improving the wear resistance, scratch resistance, etc. of the coating. Examples of such filler components include metal oxide precursors, silane coupling agents, and metal oxide fine particles.

  Examples of the metal oxide precursor include alkoxide compounds such as ethoxide compounds and methoxide compounds, oxyhalogen compounds, and acetyl compounds. As the metal oxide, one or more selected from silica, titania, zirconia, alumina, niobium oxide, and tantalum oxide can be used, and silica is particularly preferable from the economical viewpoint. The metal oxide precursor can be added in an amount up to 1.25 times the weight of the antifogging urethane component. If the amount exceeds 1.25 times, the antifogging property of the resulting film is lowered. In order to improve the abrasion resistance of the coating, the metal oxide precursor is preferably added up to 0.1 times the weight of the antifogging urethane component.

  The silane coupling agent can be added up to 0.25 times by weight with respect to the total amount of the antifogging urethane component. If the amount exceeds 0.25 times, the strength of the film obtained due to the unreacted functional group of the silane coupling agent is reduced, and problems such as stickiness on the film surface tend to occur. In addition, in order to crosslink the metal oxide derived from the precursor of the metal oxide and the urethane resin, the silane coupling agent is added up to 0.01 times by weight with respect to the total amount of the antifogging urethane component. It is preferable. It is particularly preferable that the silane coupling agent is 3-methacryloxypropyltrimethoxysilane or 3-glycidoxypropyltrimethoxysilane because a homogeneous film can be easily obtained.

  Examples of the metal oxide fine particles include metal oxide fine particles such as silica, titania, zirconia, alumina, niobium oxide, and tantalum oxide having an average particle diameter of 5 nm to 50 nm, and colloidal silica is particularly preferable. When the metal oxide fine particles are contained, since it is important not to lower the antifogging property of the antifogging film, the content thereof is 40% by weight or less with respect to the total amount of the antifogging urethane component, preferably , 20% by weight or less, more preferably 10% by weight or less. The average particle size referred to here is the visual reading of the particle size of all the particles existing within a range of 1 μm square when the cross section of the film is observed with a scanning electron microscope at a magnification of 100,000 times. The average value is calculated. This calculation is defined by the average value of each value obtained by repeating 20 times.

  As the diluent solvent, those having no active hydrogen group are preferable, and acetones and ethers can be used, and methylpropylene glycol, diacetone alcohol, and isobutyl acetate are particularly preferable.

  As means for applying the obtained coating solution to the substrate, known means such as dip coating, flow coating, spin coating, roll coating, spray coating, screen printing, flexographic printing, etc. can be adopted as the application means. After coating, the film is allowed to stand at room temperature, or preferably heated at 80 ° C. or higher, whereby an antifogging article is obtained by curing the coating. When the substrate is a mirror manufactured by the silvering method, and laminated glass having an intermediate film mainly composed of polyvinyl butyral or ethylene vinyl acetate, the heating temperature is 140 ° C. or lower, more preferably 130 ° C. or lower. It is preferable.

As a method of bringing water into contact with the cured film and removing the surfactant having unreacted active hydrogen groups from the cured film, a method of immersing an article in water, and a flow rate of 0.01 m ³ on the film A method of contacting running water / min to 0.1 m ³ / min can be employed. Here, industrial water, tap water, pure water, or the like can be used as appropriate. The contact of water with the coating is preferably performed when the temperature of the antifogging article is 60 ° C. or lower, preferably 50 ° C. or lower.

  Then, by sticking a protective film to the antifogging article, it becomes easy to load and pack the antifogging article, which is preferable because productivity is improved. As the protective film, an electrostatic patch or a film having an adhesive can be used, and a film having an adhesive is preferable. Particularly, the film having an adhesive having an adhesive strength of 1 N / 20 mm or less. Is preferred. The pressure-sensitive adhesive is preferably acrylic.

Example 1
As a surfactant having an active hydrogen group, lisinoleamidopropylethyldimonium ethosulphate (trade name “LipoquatR” manufactured by Lipochemicals Inc), polyethylene glycol having an average molecular weight of 1000 water-absorbing polyol as polyol, average of hydrophobic polyol A polycaprolactone diol having a molecular weight of 1250 (trade name “Placcel L212AL” manufactured by Daicel Chemical Industries) and 1,4 butanediol as a short-chain polyol were prepared and mixed to obtain a mixture having an active hydrogen group. The mixing ratio is 1.1 by weight for the water-absorbing polyol, 1 for the hydrophobic polyol, and 0.3 for the short-chain polyol.

  And 0.74 of the chemical species having the isocyanate group was mixed with the mixture 1 having the active hydrogen group in a weight ratio. The number of NCO groups / active hydrogen groups at this time is 1.1. Diacetone alcohol was added as a diluting solvent so that the concentration of the total amount of the antifogging urethane component was 35% by weight, and dibutyltin dilaurate was added as a curing catalyst to the total amount of the antifogging urethane component. A coating solution was prepared by adding 0.005% by weight.

  The coating solution is applied to the glass surface side of a substrate made of a 300 mm × 800 mm × 5 mm (thickness) size mirror in which a reflective layer is formed on a soda lime silicate glass by a float method by a silvering method. After heating at 120 ° C. for 30 minutes, the article is immersed in pure water at 20 ° C. for 20 minutes when the temperature of the article becomes 50 ° C. or less, so that the film thickness is 28 μm and the coating is water-absorbing. 100 antifogging articles having a contact angle of water droplets of 40 ° or less were produced in a state where the coating film did not absorb water.

  In order to confirm the anti-fogging property of the article, the appearance abnormality after leaving the article for half a year (white turbidity of the article due to the outflow of the surfactant having an unreacted active hydrogen group) is zero. Then, after cooling to 0 ° C. under conditions severer than room temperature, when the breath was applied to the coated surface, the number of cloudy articles was zero.

Example 2
The mixture 1 having active hydrogen groups is mixed with 0.6 of the above-mentioned chemical species having isocyanate groups in a weight ratio so that the number of NCO groups / active hydrogen groups is 0.9, and the coating liquid is used as a base material. 100 antifogging articles were produced in the same manner as in Example 1 except that the heating after application was 125 ° C. In order to confirm the anti-fogging property of the article, the appearance abnormality after leaving the article for half a year (white turbidity of the article due to the outflow of the surfactant having an unreacted active hydrogen group) is zero. Then, after cooling to 0 ° C. under conditions severer than room temperature, when the breath was applied to the coated surface, the number of cloudy articles was zero.

Example 3
The mixture 1 having active hydrogen groups is mixed with 0.67 chemical species having an isocyanate group in a weight ratio so that the number of NCO groups / active hydrogen groups is 1.0, and the coating liquid is used as a base material. 100 antifogging articles were produced in the same manner as in Example 1 except that the heating after coating was changed to 90 ° C. In order to confirm the anti-fogging property of the article, the appearance abnormality after leaving the article for half a year (white turbidity of the article due to the outflow of the surfactant having an unreacted active hydrogen group) is zero. Then, after cooling to 0 ° C. under conditions severer than room temperature, when the breath was applied to the coated surface, the number of cloudy articles was zero.

Example 4
After bringing the film into contact with water, the article is air-dried, and a film having an acrylic adhesive with an adhesive strength of 0.95 N / 20 mm (trade name “Elep Masking Tape N100” manufactured by Nitto Denko) is used as a protective film. 100 anti-fogging articles were produced in the same procedure as in Example 1 except that it was stuck on the coating. When the article is left for half a year and the protective film is peeled off, the number of appearance abnormalities is zero. In order to confirm the anti-fogging property of the article, the article is cooled to 0 ° C., which is severer than room temperature. When the surface was exhaled, the number of cloudy articles was zero.

Example 5
100 antifogging articles were produced in the same procedure as in Example 4 except that the coating solution was that in Example 2. When the article is left for half a year and the protective film is peeled off, the number of appearance abnormalities is zero. In order to confirm the anti-fogging property of the article, the article is cooled to 0 ° C., which is severer than room temperature. When the surface was exhaled, the number of cloudy articles was zero.

Example 6
100 antifogging articles were produced in the same procedure as in Example 4 except that the coating solution was that in Example 3. When the article is left for half a year and the protective film is peeled off, the number of appearance abnormalities is zero. In order to confirm the anti-fogging property of the article, the article is cooled to 0 ° C., which is severer than room temperature. When the surface was exhaled, the number of cloudy articles was zero.

Comparative Example 1
100 antifogging articles were produced in the same manner as in Example 1 except that water was not contacted after the coating was cured. As a result, 8 of 100 antifogging articles flowed out of the coating after being held for half a year. Became cloudy.

Comparative Example 2
100 antifogging articles were produced in the same manner as in Example 2 except that water was not contacted after the coating was cured. Nine out of 100 were produced by the outflow of the surfactant from the coating after holding for six months. Became cloudy.

Comparative Example 3
100 antifogging articles were produced in the same manner as in Example 3 except that water was not contacted after the coating was cured. As a result, 8 of 100 antifogging articles flowed out of the coating after being held for half a year. Became cloudy.

Claims (4)

In a method for obtaining an antifogging article having a cured coating formed thereon,
A surfactant having a chemical species having an NCO group and an active hydrogen group, an oxyalkylene-based water-absorbing polyol having a number average molecular weight of 400 to 5000, a hydrophobic polyol being a polyester polyol having a number average molecular weight of 500 to 2000, and a number By applying a coating liquid obtained by mixing a polyol component composed of a short-chain polyol having an average molecular weight of 60 to 200 to a substrate, water droplets in a state where the film exhibits water absorption and the film does not absorb water Is a method for obtaining an antifogging article having a contact angle of 40 ° or less,
After application of a coating solution having an NCO group number / active hydrogen group number of 0.8 or more and 1.2 or less, unreacted activity is obtained by bringing water into contact with the cured film by heating at 80 to 140 ° C. for 20 to 60 minutes. A method for producing an antifogging article, wherein a surfactant having a hydrogen group is removed from a film. 2. The antifogging according to claim 1, wherein the base material is any one of a mirror manufactured by a silvering method, and a laminated glass having an intermediate film mainly composed of polyvinyl butyral or ethylene vinyl acetate. The manufacturing method of sex goods. In a method for obtaining an antifogging article having a cured coating formed thereon,
A surfactant having a chemical species having an NCO group and an active hydrogen group, an oxyalkylene-based water-absorbing polyol having a number average molecular weight of 400 to 5000, a hydrophobic polyol being a polyester polyol having a number average molecular weight of 500 to 2000, and a number By applying a coating liquid obtained by mixing a polyol component composed of a short-chain polyol having an average molecular weight of 60 to 200 to a substrate, water droplets in a state where the film exhibits water absorption and the film does not absorb water Is a method for obtaining an antifogging article having a contact angle of 40 ° or less,
After application of a coating solution having an NCO group number / active hydrogen group number of 0.8 or more and 1.2 or less, unreacted activity is obtained by bringing water into contact with the cured film by heating at 80 to 140 ° C. for 20 to 60 minutes. The antifogging article according to claim 1 or 2, wherein a protective film is attached to the coating side of the antifogging article obtained by removing the surfactant having a hydrogen group from the coating. Manufacturing method. The method for producing an antifogging article according to claim 3, wherein the protective film is a film having an adhesive.